1. Field of the Invention
The present invention generally relates to a roller clutch. More specifically, the present invention relates to a clutch that is configured to transmit rotation in only one direction.
2. Background Information
A fishing reel, particularly a spinning reel, is provided with an anti-reverse rotation mechanism for preventing a rotor from reversing in a line-releasing direction during casting or line-winding. The anti-reverse rotation mechanism is constructed of a one-way clutch that is disposed between a reel unit and a rotor. Conventionally, a roller clutch is adopted for reducing the play (or clearance) produced during reverse rotation and is commonly known as an anti-reverse rotation one-way clutch.
In general, a roller clutch includes an outer ring, an inner ring, and a plurality of rollers. The inner ring is allowed to rotate relative to the outer ring. The rollers are disposed between the outer ring and the inner ring and are allowed to frictionally engage both of the rings while being interposed there between.
Also, the roller clutch generally comes in two forms: the inner ring idling type and the outer ring idling type. With respect to the outer ring idling type, a cam surface is formed on the outer peripheral surface of the inner ring. With respect to the inner ring idling type, a cam surface is formed on the inner peripheral surface of the outer ring. The roller clutch of this type is provided with a retainer for disposing rollers at predetermined intervals in a circumferential direction (see Japanese Patent Laid-Open Publication No. 2001-25338).
According to conventional practice, a retainer in the inner ring idling type roller clutch includes a washer shaped attachment portion, a part of which is disposed on an end portion of an outer ring, and a plurality of holding portions that protrude from one surface of the attachment portion on the inner peripheral side. Accordingly, the attachment portion is disposed not only on the outer peripheral side of the holding portions but also among the holding portions. The holding portions are disposed among a plurality of rollers, and respectively include a curved surface on one surface in a circumferential direction. The curved surface is configured to engage with the outer peripheral surface of each of the rollers. In addition, the holding portions respectively include a recessed portion for accommodating a spring member on the other surface in the circumferential direction. The spring member is constructed of a coil spring for urging the rollers in a direction that the rollers frictionally engage a cam surface. The recessed portion is constructed to be opened and have a circular shape on the other surface in the circumferential direction so that the roller is allowed to be urged in the direction that the rollers frictionally engage the cam surface.
According to the conventional configuration in which a recessed portion is formed in a holding portion and a spring member composed of a coil spring is accommodated in the recessed portion, the outer diameter of the coil spring is restricted to be equal to or less than the inner diameter of the recessed portion. Because of this, when the holding portion is designed to have a small size, the recessed portion is accordingly constructed to have a small size. Therefore, the outer diameter of the spring member must be formed to have a small size. When the outer diameter of the spring member is formed to have a small size, it will be difficult for the recessed portion to hold the spring member. For example, an operation of embedding the spring member into the recessed portion by picking the spring member with tweezers will be difficult.